1. Field of the Invention
In well drilling, with a rotary drilling rig, the drill bit and drilling pipe receive rotary motion from power equipment located on the surface. Below the drilling floor, at the ground surface, there is usually an assembly known as a rotating head that provides means for the circulation of various fluids used in the drilling. The present invention relates to rotating heads for oil and gas wells and more particularly, to an improved rotating head that enables the ease of use for the end user and also a more efficient method of assembly and disassembly to decrease down time caused by assembling or disassembling the rotating head and to decrease manufacturing costs. A conventional drilling string is inserted or “stabbed” through the rotating head assembly, including the one or two base stripper rubber units rotatably mounted in the rotating head assembly, to seal the drilling string.
In well drilling, with a rotary drilling rig, the drill bit and drilling pipe receive rotary motion from power equipment located on the surface. Below the drilling floor, at the ground surface, there is usually an assembly known as a rotating head that provides means for the circulation of various fluids used in the drilling.
U.S. Pat. No. 3,400,938, issued Sep. 10, 1960, discloses a rotating head assembly including means for assisting a circulation of lubricant around thrust bearings and sealing such bearings from well fluids and other debris. The circulation of lubricant around the bearings is assisted by providing annular recesses adjacent the bearings but is such as does not provide forced lubrication of the bearings.
The provision of forced circulation of lubricant for bearings journaling a shaft for rotation about a vertical axis is exemplified by U.S. Pat. Nos. 1,157,644, issued Oct. 19, 1915 and 4,037,890, issued Jul. 26, 1977. The former patent is provided with a bushing secured to the shaft for rotation therewith, which bushing has on its exterior surface spiral grooves which feed lubricant upwardly toward the bearing within which the shaft is journaled. The latter patent is directed to utilizing a spiral groove pump, also situated beneath the bearing, to pump lubricating oil downwardly into a lubricant reservoir extending upwardly to a point above the bearing whereby lubricating oil is caused to overflow downwardly into the bearing.
U.S. Pat. No. 3,061,387, issued Oct. 30, 1962, discloses a vertically disposed open ended tube rotatable with the shaft to cause lubricant to be continuously fed from a reservoir adjacent the lower end of the tube to the upper end of the tube whereby lubricant is fed continuously upwardly through the tube and when a critical speed is attained, the lubricant rises sufficiently high in the tube to be fed out from the top end to spray against the lower portion of an upper bearing, which oil then drains downwards toward and through a lower bearing as it returns by gravity to the reservoir.
Present day drilling operations are extremely expensive, and an effort to increase the overall efficiency of the drilling operation while minimizing expense requires the essentially continuous operation of the drilling rig. Thus, it is imperative that downtime be minimized.
In this regard, there is a need for improved sealing, lubricating, and cooling of bearings to maximize the useful life of the bearings. Seals for such bearings must effectively preclude the intrusion of well fluids or debris while at the same time ensuring retention of the bearing lubricant.
Primary features of the rotating head assembly of the present invention include an integrated seal surface on the inner barrel, a liner to seal the present invention, at least one metal encased spring loaded seal on each end of the inner barrel, a clamping mechanism, a box assembly and liner, and die spring loaded bearings. The box assembly can be utilized to facilitate rapid assembly and disassembly of the rotating head assembly. Another primary feature is mounting of the two metal encased spring loaded seals on each end of the inner barrel. The seals on the lower end will be arranged in a manner that will allow a continuous pressurized flush of the internal cavity of bearing assembly. The two seals on the top side of inner barrel will be arranged in a manner that will allow circulation for constant supply of lubrication from multiple inlet ports.
Known art may be found in U.S. Class 175, Subclasses 320, 325.1, 325.2, and 325.5 and U.S. Class 285, Subclasses 33, 268, 922, and other relevant areas.
2. Description of the Known Art
Among the patents which relate to rotating head assemblies are the following:
U.S. Pat. No. 3,992,019 (the '019 patent) issued to Crawshay on Nov. 16, 1976 discloses a core sampling drill head having powered drill chuck with jaws to grip drill rod. Head has thrust member movable by chuck actuating means between jaws retracted and jaws extended position, and precompressed chuck springs cooperating with thrust member and drill chuck so as to be movable with thrust member. Thrust member is located by releasable locking means in desired position, which means also relieve drill bearings of reaction from chuck springs. When thrust member is in jaws retracted position, chuck springs are precompressed by tension means and relatively large diameter tools can pass drill chuck. When thrust member is in jaws extended position, chuck springs cooperate with chuck, are further compressed and extend jaws to grip rod, and tension means are relieved of load from chuck springs. By precompressing and moving springs by themselves, worn drill rods can be accommodated in relatively short drill head without loss of grip. Also, with hydraulically controlled chuck actuating means, when chuck jaws are gripping rod loss of hydraulic fluid pressure does not result in loss of grip on rod as chuck springs are independent of fluid pressure.
U.S. Pat. No. 4,511,193 (the '193 patent) issued to Geczy on Apr. 16, 1985 teaches a combined radial and thrust bearing assembly for a down-hole drilling assembly to journal a shaft, mounting the drill bit, in a housing. The bearing assembly is used between a down-hole fluid powered motor and a drill bit for drilling oil wells, for example. The bearing assembly includes cooperative pairs of upper and lower inner races located on the shaft for mutual rotation. Each of the inner races includes a pair of interchangeable toroidal tracks. Cooperative pairs of upper and lower outer races are fixed against rotation in the housing. Each outer race has a pair of interchangeable toroidal tracks to selectively cooperate with the tracks of the inner races to define a toroidal channel to receive a number of bearing balls. Spring means are disposed between the upper and lower pairs of outer races and the housing and between the upper and lower pairs of outer races to provide a compliant coupling for the even distribution of radial and upwardly and downwardly directed thrust loads between the races and balls and eventual transfer to the housing. Drilling fluid is circulated through the bearing assembly for cooling and lubrication.
U.S. Pat. No. 5,028,181 issued to Jenkins et al. on Jul. 2, 1991 discloses a quick change right angle drill head that incorporates mechanism rotating components within the drill head housing thereby resulting in a more compact package which facilitates use in space-limited locations. A single push button release enlarges a chuck opening to receive a cutting tool. An internally located compression spring becomes operative when reverse thrust forces are exerted against a cutting tool. The design of the present invention may be constructed to either lock the cutting tool into the drill head chuck or release it, upon exertion of the reverse thrust forces.
U.S. Pat. No. 5,180,261 issued to Schreiber on Jan. 19, 1993 discloses a motor-operated tool for tool sockets revolving about an axis, in particular for drills or spanners. The tool comprises a tool head containing a drive spindle. The drive spindle comprises a driving opening for a drive shank of the tool socket and a plurality of ball elements for engaging a part of the drive shank to lock it in the driving opening. The ball elements preferably are adapted to lock the drive shank in the driving opening automatically and to be released by a suitable mechanism. The tool socket is designed as a drill chuck and is provided with key elements for actuating the mechanism.
U.S. Pat. No. 5,647,444 issued to Williams on Jul. 15, 1997 discloses a rotating blowout preventor having at least two rotating stripper rubber seals which provide a continuous seal about a drilling string having drilling string components of varying diameter. A stationary bowl is designed to support a blowout preventor bearing assembly and receives a swivel ball that cooperates with the bowl to self-align the blowout preventor bearing assembly and the swivel ball with respect to the fixed bowl. Chilled water is circulated through the seal boxes of the blowout preventor bearing assembly and liquid such as water is pumped into the bearing assembly annulus between the stripper rubbers to offset well pressure on the stripper rubbers.
U.S. Pat. No. 6,457,749 issued to Heijnen on Oct. 1, 2002 discloses a lock assembly for locking an outer tubular element to an inner tubular element extending through the outer tubular element for holding loads between the tubular member when lowered downhole. The assembly includes a lock mandrel connected to one of the tubular elements and the other tubular element having a recess with at least one inwardly converging side surface. A lock member, having a retracted and an expanded mode, is arranged between the first and second tubular elements. The lock member is movable relative to the recess in the retracted mode and locks against the inwardly diverging side surface when in the expanded mode.
The known art teaches the use of threads and bolts for assembly of the rotating head. The use of bolts in the known art requires users to constantly monitor the bolts to ensure that the components of the rotating head are properly attached. Further, the use of bolts requires drilling personnel or other users to expend valuable time to both assemble and disassemble the rotating head thus leading to extended downtime of the rotating head.